A spare, poignant story about a child waiting to be rescued from a refugee camp has won the £10,000 Caine prize for African writing.

Known as the African Booker, the 10-year-old prize goes to a short story by an African writer published in English. This year's winner, EC Osondu, is a former advertising copywriter from Nigeria, who now lives in the US.

His winning story, Waiting, which details the harrowing day-to-day realities of life in a refugee camp, was described as a "tour de force" by chair of judges Nana Yaa Mensah of the New Statesman. "It is powerfully written with not an ounce of fat on it – and deeply moving," she said, "describing, from a child's point of view, the dislocating experience of being a displaced person."

Published in October 2008 in Guernicamag.com, Waiting is told from the perspective of Orlando Zaki. "Orlando is taken from Orlando, Florida, which is what is written on the T-shirt given to me by the Red Cross. Zaki is the name of the town where I was found and from which I was brought to this refugee camp," writes Osondu. "Here in the camp, we wait and wait and then wait some more. It is the only thing we do. We wait for the food trucks to come and then we form a straight line and then we wait a few minutes for the line to scatter, then we wait for the fight to begin, and then we fight and struggle and bite and kick and curse and tear and grab and run."

Osondu was announced as winner of the Caine prize at a dinner held yesterday evening at the Bodleian Library in Oxford. He wins £10,000, and the opportunity to take up a month's residence at Georgetown University in Washington DC as a writer in residence, with all travel and living expenses covered.

Previously shortlisted for the 2007 Caine prize for his story Jimmy Carter's Eyes, this year Osondu saw off competition from Ghanaian writer Mamle Kabu's The End of Skill, Kenyan Parselelo Kantai's You Wreck Her, South African Alistair Morgan's Icebergs and Kenyan Mukoma wa Ngugi's How Kamau wa Mwangi Escaped into Exile to take the award.

Mensah was joined on the judging panel by Professor Jon Cook of the University of East Anglia, novelist and Georgetown University professor Jennifer Natalya Fink, Guardian journalist and author Hannah Pool, and Mohammed Umar, the Nigerian novelist, journalist and bookseller.

Last year's prize was won by South African author Henrietta Rose-Innes for Poison. Previous winners of the award, which counts JM Coetzee, Wole Soyinka, Nadine Gordimer and Chinua Achebe amongst its patrons, also include Uganda's Monica Arac de Nyeko for Jambula Tree and Zimbabwe's Brian Chikwava.